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IMPROVEMENT IN ELLrPsoenAPHS.

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TO ALL WHOM IT MAY CON CERN Be it known that I, HONESTUs M. ALBEE, ofWebster, in the county of Worcester, and State of Massachu-J setts, haveinventeda new and improved Ellipsograph; and I do hereby declare thatthe following is a full, clear, and exact description thereof, whichwill enable others skilled in the art to make and use the same,reference being had to the accompanying drawings, forming part of thisspecification, in which- Figure 1 represents a side elevation of thisinvention.

Figure 2 is a diagram showing the manner in which my ellipsograph isused.

Similar letters of reference indicate like parts.

This invention -consists in the arrangement of au arm provided with anadjustable point in combination with one leg of an ordinary compass, theother leg of which is constructed to receive a pencil or pen such amanner that when'the adjustable point is-removed from the leg of thecompass to a distance equal to the difference of the major and minoraxis of the ellipse to be described, and said point and leg are movedalong on the I two catheti of a right-angled triangle, or in the groovesof a trammel, the pen or pencil connected to the compass will describe aportion of an ellipse, and by shifting the right-angled triangle andrepeating the operation, a complete ellipse of any desired proportioncan be described.

A represents a compass of any desired construction, and arranged so thatits two legs, B C, can be adjusted at any desired distance apart by asegmental guide, a, and set-screw, b, or by anyother suitable means. vOnthe leg B of'this compass, is secured anal-rn, D, which-` may be rigidlyattached to the same, or which may be held in place by a set-screw, sothat it can bereadil'y removed if it is not to be used, and that it doesnot interfere with the ordinary use of the compass. Said arm forms theguide for a point, c, which is adjustable thereon by means of aset-screw, so that it can be secured at any desired distance from thepoint of the leg B. The leg C is provided with a socket, e, to receive apen or pencil, and said socket may beconstructed in any desirablemanner.

When theinstrument is to be used for the purpose of describing anellipse, I first draw two lines at right angles to each other from thecentre of the ellipse to be described, in the direction of themajor andminor axis of said ellipse, and then I adjust the point e so that itsdistance from the point B is equal to the difference between the majorand minor axis, and open the leg C so that the distance of the point ofthe vpen or pencil from the pointe is equal toone-half the major, andfrom the point B equal to one-halt` the minor axis. In this position Isecure the several parts of the compass, and then I adjust in one of theright angles enclosed by the major and minor axis, an ordinary woodensquare, as shown in fig. 2,. andbymo'ving the points e ,B along on thecatheti of said square, the pen or pencil describes one-quarter of thedesired ellipse. By changing the position of the square to the adjoiningangle and repeating the operation, the next quarter of the ellipse isdescribed, and so on until the ellipse is completed. i

The principal advantage of this instrument is its great simplicity,nothing being required, in addition to an ordinary compass or case ofdrawing instruments, but the arm D, with its adjustable point e; and bysecuring said arm on one of the legs of the compass, an ellipsograph isobtained with which ellipses of any desired form or proportion can bedrawn with the greatest ease and facility.

What Iclaim as new, and desire to secure by Letters Patent, is-

The arm' D, with its Aadjustable point c,-in combination with thecompass A, constructed and operating s'ubstantially as and for thepurpose described. v f

i The above specication of my invention signed by me this twelfth day ofJune, 1866.

HONESTUS M. ALBEE.

Witnesses:

WM. MeNAMARA, W. HAUFF.

